Ion assisted deposition top coat of rare-earth oxide

ABSTRACT

A method of manufacturing an article comprises providing an article. An ion assisted deposition (IAD) process is performed to deposit a second protective layer over a first protective layer. The second protective layer is a plasma resistant rare earth oxide having a thickness of less than 50 microns and a porosity of less than 1%. The second protective layer seals a plurality of cracks and pores of the first protective layer.

RELATED APPLICATIONS

This patent application is a divisional of U.S. patent application Ser.No. 14/262,644, filed Apr. 25, 2014 and entitled “Ion AssistedDeposition Top Coat of Rare-Earth Oxide,” which is herein incorporatedby reference.

TECHNICAL FIELD

Embodiments of the present invention relate, in general, to chambercomponents having an ion assisted deposition (IAD) deposited thin filmplasma resistant protective layer.

BACKGROUND

In the semiconductor industry, devices are fabricated by a number ofmanufacturing processes producing structures of an ever-decreasing size.Some manufacturing processes such as plasma etch and plasma cleanprocesses expose a substrate to a high-speed stream of plasma to etch orclean the substrate. The plasma may be highly corrosive, and may corrodeprocessing chambers and other surfaces that are exposed to the plasma.

SUMMARY

In an example implementation, a chamber component comprises a body, afirst protective layer on at least one surface of the body, and aconformal second protective layer that covers at least a portion of thefirst protective layer. The first protective layer comprises a plasmaresistant ceramic, wherein the first protective layer has a thickness ofgreater than approximately 50 microns and comprises a plurality ofcracks and pores. The second protective layer comprises a plasmaresistant rare earth oxide, wherein the second protective layer has athickness of less than 50 microns, has a porosity of less than 1%, andseals the plurality of cracks and pores of the first protective layer.

In another example implementation, a method comprises performing ionassisted deposition (IAD) to deposit a second protective layer on atleast a portion of a first protective layer that is on a surface of anarticle, the second protective layer comprising a plasma resistant rareearth oxide, wherein the second protective layer has a thickness of lessthan 50 microns, has a porosity of less than 1%, and seals a pluralityof cracks and pores of the first protective layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that differentreferences to “an” or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean at leastone.

FIG. 1 depicts a sectional view of one embodiment of a processingchamber.

FIG. 2A depicts a deposition mechanism applicable to a variety ofdeposition techniques utilizing energetic particles such as ion assisteddeposition (IAD).

FIG. 2B depicts a schematic of an IAD deposition apparatus.

FIGS. 3A-4C illustrate cross sectional side views of articles covered byone or more thin film protective layers.

FIG. 5 illustrates a chamber liner having a rare earth oxide plasmaresistant layer, in accordance with one embodiment.

FIG. 6A illustrates one embodiment of a process for forming one or moreprotective layers over an article.

FIG. 6B illustrates one embodiment of a process for forming a thin filmprotective layer over a body of an article using an IAD or PVD with ametallic target.

FIGS. 7A-7E illustrate scanning electron microscope (SEM) images ofarticles having a thin film protective layer formed from a ceramiccompound of Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂ deposited over aplasma sprayed protective layer also formed from the ceramic compound ofY₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.

FIGS. 8 and 9 illustrate erosion rates under CH₄—Cl₂ and CHF₃—NF₃—Cl₂chemistries respectively for thin film protective layers formed inaccordance with embodiments of the present invention.

FIGS. 10-11 illustrate roughness profiles under CH₄—Cl₂ and CHF₃—NF₃—Cl₂chemistries respectively for thin film protective layers formed inaccordance with embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention provide an article such as achamber component for an etch reactor having a thin film protectivelayer on one or more plasma facing surfaces of the article. Theprotective layer may have a thickness up to approximately 300 μm, andmay provide plasma erosion resistance for protection of the article. Theprotective layer may be formed on the article using ion assisteddeposition (IAD) (e.g., using electron beam IAD (EB-IAD) or ion beamsputtering IAD (IBS-IAD)) or physical vapor deposition (PVD). The thinfilm protective layer may be Y₃Al₅O₁₂, Y₂O₃, Y₄Al₂O₉, Er₂O₃, Gd₂O₃,Er₃Al₅O₁₂, Gd₃Al₅O₁₂, a ceramic compound comprising Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂, or another rare-earth oxide. In oneembodiment, IAD or PVD is performed using a metallic target, and therare earth oxide is formed in situ. The improved erosion resistanceprovided by the thin film protective layer may improve the service lifeof the article, while reducing maintenance and manufacturing cost.Additionally, the IAD coating can be deposited as a top coat over aplasma sprayed coating. The IAD coating can seal pores and cracks in theplasma sprayed coating to significantly reduce an amount of reactivityof process gases with the chamber component as well as a level of tracemetal contamination. The IAD coating can also embed any loose particlesthat were on the plasma sprayed coating to reduce particle defects.

FIG. 1 is a sectional view of a semiconductor processing chamber 100having one or more chamber components that are coated with a thin filmprotective layer in accordance with embodiments of the presentinvention. The processing chamber 100 may be used for processes in whicha corrosive plasma environment is provided. For example, the processingchamber 100 may be a chamber for a plasma etch reactor (also known as aplasma etcher), a plasma cleaner, and so forth. Examples of chambercomponents that may include a thin film protective layer include asubstrate support assembly 148, an electrostatic chuck (ESC) 150, a ring(e.g., a process kit ring or single ring), a chamber wall, a base, a gasdistribution plate, a showerhead, a chamber liner, a liner kit, ashield, a plasma screen, a flow equalizer, a cooling base, a chamberviewport, a chamber lid 104, a nozzle, a flow equalizer (FEQ), and soon. In one particular embodiment, the protective layer is applied over achamber lid 104 and/or a chamber nozzle 132.

The thin film protective layer, which is described in greater detailbelow, is a rare earth oxide layer deposited by ion assisted deposition(IAD) or physical vapor deposition (PVD). The thin film protective layermay include Y₂O₃ and Y₂O₃ based rare earth oxide composites, Er₂O₃ andEr₂O₃ based rare earth oxide composites, Gd₂O₃ and Gd₂O₃ based rareearth oxide composites, Nd₂O₃ and Nd₂O₃ based ceramics, Er based rareearth oxide composites, Ga based rare earth oxide composites, or AlN. Invarious embodiments, the thin film protective layer may be composed ofY₃Al₅O₁₂ (YAG), Y₄Al₂O₉ (YAM), Er₃Al₅O₁₂ (EAG), Gd₃Al₅O₁₂ (GAG), YAlO₃(YAP), Er₄Al₂O₉ (EAM), ErAlO₃ (EAP), Gd₄Al₂O₉ (GdAM), GdAlO₃ (GdAP),Nd₃Al₅O₁₂ (NdAG), Nd₄Al₂O₉ (NdAM), NdAlO₃ (NdAP), and/or a ceramiccompound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂. The thinfilm protective layer may also be Er—Y compositions (e.g., Er 80 wt %and Y 20 wt %), Er—Al—Y compositions (e.g., Er 70 wt %, Al 10 wt %, andY 20 wt %), Er—Y—Zr compositions (e.g., Er 70 wt %, Y 20 wt % and Zr 10wt %), or Er—Al compositions (e.g., Er 80 wt % and Al 20 wt %). Notethat wt % means percentage by weight. In contrast, mol % is molar ratio.

The thin film protective layer may also be based on a solid solutionformed by any of the aforementioned ceramics. With reference to theceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂,in one embodiment, the ceramic compound includes 62.93 molar ratio (mol%) Y₂O₃, 23.23 mol % ZrO₂ and 13.94 mol % Al₂O₃. In another embodiment,the ceramic compound can include Y₂O₃ in a range of 50-75 mol %, ZrO₂ ina range of 10-30 mol % and Al₂O₃ in a range of 10-30 mol %. In anotherembodiment, the ceramic compound can include Y₂O₃ in a range of 40-100mol %, ZrO₂ in a range of 0-60 mol % and Al₂O₃ in a range of 0-10 mol %.In another embodiment, the ceramic compound can include Y₂O₃ in a rangeof 40-60 mol %, ZrO₂ in a range of 30-50 mol % and Al₂O₃ in a range of10-20 mol %. In another embodiment, the ceramic compound can includeY₂O₃ in a range of 40-50 mol %, ZrO₂ in a range of 20-40 mol % and Al₂O₃in a range of 20-40 mol %. In another embodiment, the ceramic compoundcan include Y₂O₃ in a range of 70-90 mol %, ZrO₂ in a range of 0-20 mol% and Al₂O₃ in a range of 10-20 mol %. In another embodiment, theceramic compound can include Y₂O₃ in a range of 60-80 mol %, ZrO₂ in arange of 0-10 mol % and Al₂O₃ in a range of 20-40 mol %. In anotherembodiment, the ceramic compound can include Y₂O₃ in a range of 40-60mol %, ZrO₂ in a range of 0-20 mol % and Al₂O₃ in a range of 30-40 mol%. In other embodiments, other distributions may also be used for theceramic compound.

In one embodiment, an alternative ceramic compound that includes acombination of Y₂O₃, ZrO₂, Er₂O₃, Gd₂O₃ and SiO₂ is used for theprotective layer. In one embodiment, the alternative ceramic compoundcan include Y₂O₃ in a range of 40-45 mol %, ZrO₂ in a range of 0-10 mol%, Er2O3 in a range of 35-40 mol %, Gd2O3 in a range of 5-10 mol % andSiO2 in a range of 5-15 mol %. In a first example, the alternativeceramic compound includes 40 mol % Y₂O₃, 5 mol % ZrO₂, 35 mol % Er₂O₃, 5mol % Gd₂O₃ and 15 mol % SiO₂. In a second example, the alternativeceramic compound includes 45 mol % Y₂O₃, 5 mol % ZrO₂, 35 mol % Er₂O₃,10 mol % Gd₂O₃ and 5 mol % SiO₂. In a third example, the alternativeceramic compound includes 40 mol % Y₂O₃, 5 mol % ZrO₂, 40 mol % Er₂O₃, 7mol % Gd₂O₃ and 8 mol % SiO₂.

In one embodiment, an alternative ceramic compound that includes acombination of Y₂O₃, ZrO₂, Er₂O₃, and Al₂O₃ is used for the protectivelayer. In one embodiment, the alternative ceramic compound includes 25mol % Y₂O₃, 25 mol % ZrO₂, 25 mol % Er₂O₃, and 25 mol % Al₂O₃.

In one embodiment, an alternative ceramic compound that includes acombination of Y₂O₃, Gd₂O₃ and Al₂O₃ is used for the protective layer.The alternative ceramic compound may include 6.9-22.1 mol % Y₂O₃,14.1-44.9 mol % Gd₂O₃, and 33.0-79 mol % Al₂O₃. In one embodiment, thealternative ceramic compound includes 22.1 mol % Y₂O₃, 44.9 mol % Gd₂O₃and 33.0 mol % Al₂O₃. In another embodiment, the alternative ceramiccompound includes 16.5 mol % Y₂O₃, 33.5 mol % Gd₂O₃ and 50.0 mol %Al₂O₃. In another embodiment, the alternative ceramic compound includes12.5 mol % Y₂O₃, 25.5 mol % Gd₂O₃ and 62.0 mol % Al₂O₃. In anotherembodiment, the alternative ceramic compound includes 6.9 mol % Y₂O₃,14.1 mol % Gd₂O₃ and 79.0 mol % Al₂O₃.

Any of the aforementioned thin film protective layers may include traceamounts of other materials such as ZrO₂, Al₂O₃, SiO₂, B₂O₃, Er₂O₃,Nd₂O₃, Nb₂O₅, CeO₂, Sm₂O₃, Yb₂O₃, or other oxides.

The thin film protective layer may be an IAD coating applied overdifferent ceramic articles including oxide based ceramics, Nitride basedceramics and Carbide based ceramics. Examples of oxide based ceramicsinclude SiO₂ (quartz), Al₂O₃, Y₂O₃, and so on. Examples of Carbide basedceramics include SiC, Si—SiC, and so on. Examples of Nitride basedceramics include AlN, SiN, and so on. The thin film protective layer mayalso be an IAD coating applied over a plasma sprayed protective layer.The plasma sprayed protective layer may be Y₃Al₅O₁₂, Y₂O₃, Y₄Al₂O₉,Er₂O₃, Gd₂O₃, Er₃Al₅O₁₂, Gd₃Al₅O₁₂, a ceramic compound comprisingY₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂, or another ceramic.

As illustrated, the lid 130 and nozzle 132 each have a thin filmprotective layer 133, 134, in accordance with one embodiment. However,it should be understood that any of the other chamber components, suchas those listed above, may also include a thin film protective layer.For example, an inner liner and/or outer liner of the processing chamber100 may include the thin film protective layer.

In one embodiment, the processing chamber 100 includes a chamber body102 and a lid 130 that enclose an interior volume 106. The lid 130 mayhave a hole in its center, and a nozzle 132 may be inserted into thehole. The chamber body 102 may be fabricated from aluminum, stainlesssteel or other suitable material. The chamber body 102 generallyincludes sidewalls 108 and a bottom 110. Any of the lid 130, nozzle 132,sidewalls 108 and/or bottom 110 may include a plasma sprayed protectivelayer and/or a thin film protective layer that may act as a top coatover the plasma sprayed protective layer.

An outer liner 116 may be disposed adjacent the sidewalls 108 to protectthe chamber body 102. The outer liner 116 may include a plasma sprayedprotective layer and/or a thin film protective layer. In one embodiment,the outer liner 116 is fabricated from aluminum oxide. In oneembodiment, the outer liner 116 is fabricated from an aluminum alloy(e.g., 6061 Aluminum) with a plasma sprayed Y₂O₃ protective layer. Thethin film protective layer may act as a top coat over the Y₂O₃protective layer on the outer liner.

An exhaust port 126 may be defined in the chamber body 102, and maycouple the interior volume 106 to a pump system 128. The pump system 128may include one or more pumps and throttle valves utilized to evacuateand regulate the pressure of the interior volume 106 of the processingchamber 100.

The lid 130 may be supported on the sidewall 108 of the chamber body102. The lid 130 may be opened to allow access to the interior volume106 of the processing chamber 100, and may provide a seal for theprocessing chamber 100 while closed. A gas panel 158 may be coupled tothe processing chamber 100 to provide process and/or cleaning gases tothe interior volume 106 through the nozzle 132. The lid 130 may be aceramic such as Al₂O₃, Y₂O₃, YAG, SiO₂, AlN, SiN, SiC, Si—SiC, or aceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.The nozzle 132 may also be a ceramic, such as any of those ceramicsmentioned for the lid. The lid 130 and/or nozzle 132 may be coated witha thin film protective layer 133, 134, respectively.

Examples of processing gases that may be used to process substrates inthe processing chamber 100 include halogen-containing gases, such asC₂F₆, SF₆, SiCl₄, HBr, NF₃, CF₄, CHF₃, CH₂F₃, F, NF₃, Cl₂, CCl₄, BCl₃and SiF₄, among others, and other gases such as O₂, or N₂O. Examples ofcarrier gases include N₂, He, Ar, and other gases inert to process gases(e.g., non-reactive gases). A substrate support assembly 148 is disposedin the interior volume 106 of the processing chamber 100 below the lid130. The substrate support assembly 148 holds the substrate 144 duringprocessing. A ring 146 (e.g., a single ring) may cover a portion of theelectrostatic chuck 150, and may protect the covered portion fromexposure to plasma during processing. The ring 146 may be silicon orquartz in one embodiment.

An inner liner 118 may be coated on the periphery of the substratesupport assembly 148. The inner liner 118 may be a halogen-containinggas resist material such as those discussed with reference to the outerliner 116. In one embodiment, the inner liner 118 may be fabricated fromthe same materials of the outer liner 116. Additionally, the inner liner118 may be coated with a plasma sprayed protective layer and/or an IADdeposited thin film protective layer.

In one embodiment, the substrate support assembly 148 includes amounting plate 162 supporting a pedestal 152, and an electrostatic chuck150. The electrostatic chuck 150 further includes a thermally conductivebase 164 and an electrostatic puck 166 bonded to the thermallyconductive base by a bond 138, which may be a silicone bond in oneembodiment. The mounting plate 162 is coupled to the bottom 110 of thechamber body 102 and includes passages for routing utilities (e.g.,fluids, power lines, sensor leads, etc.) to the thermally conductivebase 164 and the electrostatic puck 166.

The thermally conductive base 164 and/or electrostatic puck 166 mayinclude one or more optional embedded heating elements 176, embeddedthermal isolators 174 and/or conduits 168, 170 to control a lateraltemperature profile of the support assembly 148. The conduits 168, 170may be fluidly coupled to a fluid source 172 that circulates atemperature regulating fluid through the conduits 168, 170. The embeddedisolator 174 may be disposed between the conduits 168, 170 in oneembodiment. The heater 176 is regulated by a heater power source 178.The conduits 168, 170 and heater 176 may be utilized to control thetemperature of the thermally conductive base 164, thereby heating and/orcooling the electrostatic puck 166 and a substrate (e.g., a wafer) 144being processed. The temperature of the electrostatic puck 166 and thethermally conductive base 164 may be monitored using a plurality oftemperature sensors 190, 192, which may be monitored using a controller195.

The electrostatic puck 166 may further include multiple gas passagessuch as grooves, mesas and other surface features, that may be formed inan upper surface of the puck 166. The gas passages may be fluidlycoupled to a source of a heat transfer (or backside) gas such as He viaholes drilled in the puck 166. In operation, the backside gas may beprovided at controlled pressure into the gas passages to enhance theheat transfer between the electrostatic puck 166 and the substrate 144.

The electrostatic puck 166 includes at least one clamping electrode 180controlled by a chucking power source 182. The electrode 180 (or otherelectrode disposed in the puck 166 or base 164) may further be coupledto one or more RF power sources 184, 186 through a matching circuit 188for maintaining a plasma formed from process and/or other gases withinthe processing chamber 100. The sources 184, 186 are generally capableof producing RF signal having a frequency from about 50 kHz to about 3GHz and a power of up to about 10,000 Watts.

FIG. 2A depicts a deposition mechanism applicable to a variety ofdeposition techniques utilizing energetic particles such as ion assisteddeposition (IAD) and PVD. Some embodiments are discussed with referenceto IAD. However, it should be understood that alternative embodimentsmay also be used with PVD deposition techniques. Exemplary IAD methodsinclude deposition processes which incorporate ion bombardment, such asevaporation (e.g., activated reactive evaporation (ARE) or electron beamion assisted deposition (EB-IAD)) and sputtering (e.g., ion beamsputtering ion assisted deposition (IBS-IAD)) in the presence of ionbombardment to form plasma resistant coatings as described herein.EB-IAD may be performed by evaporation. IBS-IAD may be performed bysputtering a solid target material.

As shown, the thin film protective layer 215 is formed on an article 210or on multiple articles 210A, 210B by an accumulation of depositionmaterials 202 in the presence of energetic particles 203 such as ions(e.g., Oxygen ions or Nitrogen ions). The articles 210A, 210B may bemetal (e.g., Aluminum alloys, stainless steel, etc.), ceramic (e.g.,Al₂O₃, Y₂O₃, AlN, SiO₂, etc.), or polymer based materials. The articles210A, 201B may already have a plasma spray coating such as a Y₂O₃coating on at least one surface. The IAD or PVD process may be performedto provide a top coat over the plasma spray coating.

The deposition materials 202 may include atoms, ions, radicals, and soon. The energetic particles 203 may impinge and compact the thin filmprotective layer 215 as it is formed. Any of the IAD or PVD methods maybe performed in the presence of a reactive gas species, such as O₂, N₂,halogens, etc. Such reactive species may burn off surface organiccontaminants prior to and/or during deposition.

In one embodiment, EB-IAD is utilized to form the thin film protectivelayer 215. In another embodiment, IBS-IAD is utilized to form the thinfilm protective layer 215. Alternatively, PVD is utilized to form thethin film protective layer 215. FIG. 2B depicts a schematic of an IADdeposition apparatus. As shown, a material source 250 provides a flux ofdeposition materials 202 while an energetic particle source 255 providesa flux of the energetic particles 203, both of which impinge upon thearticle 210, 210A, 210B throughout the IAD process. The energeticparticle source 255 may be an Oxygen, Nitrogen or other ion source. Theenergetic particle source 255 may also provide other types of energeticparticles such as inert radicals, neutron atoms, and nano-sizedparticles which come from particle generation sources (e.g., fromplasma, reactive gases or from the material source that provide thedeposition materials).

IAD coating target material can be calcined powders, preformed lumps(e.g., formed by green body pressing, hot pressing, and so on), asintered body (e.g., having 50-100% density), or a machined body (e.g.,can be ceramic, metal, or a metal alloy). In one embodiment, thematerial source (e.g., target body) used to provide the depositionmaterials is a ceramic corresponding to the same ceramic that the thinfilm protective layer 215 is to be composed of. In one embodiment, thematerial source is a bulk sintered ceramic corresponding to the sameceramic that the thin film protective layer 215 is to be composed of.For example, the material source may be a bulk sintered ceramic compoundbody, or bulk sintered YAG, Er₂O₃, Gd₂O₃, Er₃Al₅O₁₂, or Gd₃Al₅O₁₂, orother mentioned ceramics. Other target materials may also be used, suchas powders, calcined powders, preformed material (e.g., formed by greenbody pressing or hot pressing), or a machined body (e.g., fusedmaterial). All of the different types of material sources 250 are meltedinto molten material sources during deposition. However, different typesof starting material take different amounts of time to melt. Fusedmaterials and/or machined bodies may melt the quickest. Preformedmaterial melts slower than fused materials, calcined powders melt slowerthan preformed materials, and standard powders melt more slowly thancalcined powders.

In another embodiment, the material source (e.g., target body) used toprovide the deposition materials is a metallic target. Use of a metallictarget rather than a ceramic target typically increases the depositionrate for IAD or PVD deposited layers. The metallic target material maybe evaporated or sputtered, and may react with one or more gases in situto form a ceramic layer. In one embodiment, Oxygen or Nitrogen radicalsare flowed into a deposition chamber during the IAD deposition. Theevaporated or sputtered metal reacts with the Oxygen or Nitrogenradicals to form an oxide or nitride ceramic layer. For example, aYttrium metal target may be evaporated or sputtered, and may react withOxygen radicals to form a Y₂O₃ IAD deposited layer. In another examplean Aluminum metal target is evaporated or sputtered and reacts withNitrogen radicals to form an AlN IAD deposited layer. Other example rareearth metals that may be used as the target include Aluminum, Erbium,and Gadolinium.

To form complex oxide compositions, various metal alloys may be used asthe target material. Some example metal alloys that may be used todeposit plasma resistant rare earth oxide layers include a YttriumZirconium alloy; a Yttrium, Zirconium, Aluminum alloy; an ErbiumAluminum alloy, a Gadolinium Aluminum alloy; a Yttrium, Erbium,Zirconium, Aluminum alloy; a Yttrium, Erbium, Zirconium, Gadolinium,Silicon alloy; and a Yttrium, Gadolinium, Aluminum alloy.

The flow rate of the Oxygen or Nitrogen radicals may be adjusted tocontrol an Oxygen content or Nitrogen content in the thin filmprotective layer 215 that is formed. In one embodiment, a low flow rateof Oxygen or Nitrogen radicals is initially used to deposit a metallictype coating that has a low concentration of Oxygen or Nitrogen. Thismay minimize or eliminate any mismatch stress induced by physicalproperty differences between the thin film protective layer 215 and thearticle 210. The flow rate of Oxygen or Nitrogen radicals may begradually increased as the deposition process continues. The flow ratemay be increased linearly, exponentially, or logarithmically during thedeposition process for example. The top of the thin film protectivelayer 215 may then have a high concentration of Oxygen or Nitrogen, andbe an oxide or nitride. For example, a deposition can be started over asubstrate made of an aluminum alloy by evaporation of Al metal. After 1μm of deposition of an essentially Aluminum coating with a minimalconcentration of Oxygen, the concentration of Oxygen radicals inside thechamber may be increased to cause another 1 μm of deposition to be Alwith a larger concentration of Oxygen, and the concentration of Oxygenradicals inside the chamber may be further increased to cause the restof the coating to be Al₂O₃. The ion assist can also include a neutralion (e.g., Ar). If the material loses oxygen during evaporation anddeposition, the oxygen deficiency can be compensated by bleeding oxygeninto the chamber.

IAD may utilize one or more plasmas or beams (e.g., electron beams) toprovide the material and energetic ion sources. Reactive species mayalso be provided during deposition of the plasma resistant coating. Inone embodiment, the energetic particles 203 include at least one ofnon-reactive species (e.g., Ar) or reactive species (e.g., O or N). Forexample, Oxygen ions or Nitrogen ions may be used to bombard the article210 during the IAD deposition. These Oxygen or Nitrogen ions mayadditionally react with the evaporated or sputtered metal in situ. Thebombardment of Oxygen or Nitrogen ions may be used instead of or inaddition to the flowing of Oxygen or Nitrogen radicals into theprocessing chamber to react with the evaporated or sputtered metal insitu.

In further embodiments, reactive species such as CO and halogens (Cl, F,Br, etc.) may also be introduced during the formation of a plasmaresistant coating to further increase the tendency to selectively removedeposited material most weakly bonded to the thin film protective layer215.

With IAD processes, the energetic particles 203 may be controlled by theenergetic ion (or other particle) source 255 independently of otherdeposition parameters. The energy (e.g., velocity), density and incidentangle of the energetic ion flux may be adjusted to control acomposition, structure, crystalline orientation and grain size of thethin film protective layer. Additional parameters that may be adjustedare a temperature of the article during deposition as well as theduration of the deposition.

The ion assist energy is used to densify the coating and to acceleratethe deposition of the material on the surface of the substrate. Ionassist energy can be varied using both the voltage and current of theion source. The voltage and current can be adjusted to achieve high andlow coating density, to manipulate a stress of the coating and also acrystallinity of the coating. The ion assist energy may range fromapproximately 50-500 Volts (V) and approximately 1-50 amps (A). The ionassist energy can also be used to intentionally change a stoichiometryof the coating. For example, a metallic target can be used duringdeposition, and converted to a metal oxide.

Coating temperature can be controlled by using heaters to heat adeposition chamber and/or a substrate and by adjusting a depositionrate. In one embodiment, an IAD deposition chamber (and the articletherein) is heated to a starting temperature of 160° C. or higher priorto deposition. In one embodiment, the starting temperature is 160° C. to500° C. In one embodiment, the starting temperature is 200° C. to 270°C. The temperature of the chamber and of the article may then bemaintained at the starting temperature during deposition. In oneembodiment, the IAD chamber includes heat lamps which perform theheating. In an alternative embodiment, the IAD chamber and article arenot heated. If the chamber is not heated, it will naturally increase intemperature to about 160° C. as a result of the IAD process. A highertemperature during deposition may increase a density of the protectivelayer but may also increase a mechanical stress of the protective layer.Active cooling can be added to the chamber to maintain a low temperatureduring coating. The low temperature may be maintained at any temperatureat or below 160° C. down to 0° C. in one embodiment. In one embodiment,the article is cooled to maintain a temperature at or below 150° C.during deposition. The article may be maintained at or below 150° C. toprevent the plasma sprayed protective layer from delaminating from thearticle during the IAD deposition. Deposition temperature can be used toadjust film stress, crystallinity, and other coating properties.

Additional parameters that may be adjusted are working distance 270 andangle of incidence 272. The working distance 270 is the distance betweenthe material source 250 and the article 210A, 210B. In one embodiment,the working distance is 0.2 to 2.0 meters, with a working distance of ator below 1.0 meters in one particular embodiment. Decreasing the workingdistance increases a deposition rate and increases an effectiveness ofthe ion energy. However, decreasing the working distance below aparticular point may reduce a uniformity of the protective layer. Theworking distance can be varied to achieve a coating with a highestuniformity. Additionally, working distance may affect deposition rateand density of the coating. In one embodiment, a working distance ofless than 1.0 meters is used to provide an increased deposition rate atthe expense of introducing a non-uniformity of up to 5-10% into the thinfilm protective layer.

The angle of incidence is an angle at which the deposition materials 202strike the articles 210A, 210B. The angle of incidence can be varied bychanging the location and/or orientation of the substrate. In oneembodiment the angle of incidence is 10-90 degrees, with an angle ofincidence of about 30 degrees in one particular embodiment. Byoptimizing the angle of incidence, a uniform coating in threedimensional geometries can be achieved.

IAD coatings can be applied over a wide range of surface conditions withroughness from about 0.5 micro-inches (pin) to about 180 μin. However,smoother surface facilitates uniform coating coverage. The coatingthickness can be up to about 1000 microns (μm). In production, coatingthickness on components can be assessed by purposely adding a rare earthoxide based colored agent such Nd₂O₃, Sm₂O₃, Er₂O₃, etc. at the bottomof a coating layer stack. The thickness can also be accurately measuredusing ellipsometry.

IAD coatings can be amorphous or crystalline depending on the rare-earthoxide composite used to create the coating. For example EAG and YAG areamorphous coatings whereas Er₂O₃ and the ceramic compound comprisingY₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂ are typically crystalline.Amorphous coatings are more conformal and reduce lattice mismatchinduced epitaxial cracks whereas crystalline coatings are more erosionresistant.

Coating architecture can be a bi-layer or a multi-layer structure. In abilayer architecture, an amorphous layer can be deposited as a bufferlayer to minimize epitaxial cracks followed by a crystalline layer onthe top which might be erosion resistant. In a multi-layer design, layermaterials may be used to cause a smooth thermal gradient from thesubstrate to the top layer.

Co-deposition of multiple targets using multiple electron beam (e-beam)guns can be achieved to create thicker coatings as well as layeredarchitectures. For example, two targets having the same material typemay be used at the same time. Each target may be bombarded by adifferent electron beam gun. This may increase a deposition rate and athickness of the protective layer. In another example, two targets maybe different ceramic materials or different metallic materials. A firstelectron beam gun may bombard a first target to deposit a firstprotective layer, and a second electron beam gun may subsequentlybombard the second target to form a second protective layer having adifferent material composition than the first protective layer.Alternatively, the two electron beam guns may bombard the two targetssimultaneously to create a complex ceramic compound. Accordingly, twodifferent metallic targets may be used rather than a single metal alloyto form a complex ceramic compound.

Post coating heat treatment can be used to achieve improved coatingproperties. For example, it can be used to convert an amorphous coatingto a crystalline coating with higher erosion resistance. Another exampleis to improve the coating to substrate bonding strength by formation ofa reaction zone or transition layer.

In one embodiment, articles are processed in parallel in an IAD chamber.For example, up to five lids and/or nozzles may be processed in parallelin one embodiment. Each article may be supported by a different fixture.Alternatively, a single fixture may be configured to hold multiplearticles. The fixtures may move the supported articles duringdeposition.

In one embodiment, a fixture to hold an article such as a chamber linercan be designed out of metal components such as cold rolled steel orceramics such as Al₂O₃, Y₂O₃, etc. The fixture may be used to supportthe chamber liner above or below the material source and electron beamgun. The fixture can have a chucking ability to chuck the lid and/ornozzle for safer and easier handling as well as during coating. Also,the fixture can have a feature to orient or align the chamber liner. Inone embodiment, the fixture can be repositioned and/or rotated about oneor more axes to change an orientation of the supported chamber liner tothe source material. The fixture may also be repositioned to change aworking distance and/or angle of incidence before and/or duringdeposition. The fixture can have cooling or heating channels to controlthe article temperature during coating. The ability or reposition androtate the chamber liner may enable maximum coating coverage of 3Dsurfaces such as holes since IAD is a line of sight process.

TABLE 1 Material properties for IAD deposited YAG, Er₂O₃, EAG andceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.Ceramic Property 92% Al₂O₃ Cmpd. YAG Er₂O₃ EAG Y₂O₃ YZ20 Crystal C A A CA C C Structure Breakdown 363 427 1223 527 900 1032 423 Voltage (V) (5μm) (5 μm) (5 μm) Volume >0.01E16 4.1E16 11.3E16 — — — — Resistivity (Ω· cm) Dielectric 9.2 9.83 +/− 0.04 9.76 +/− 0.01 9.67 9.54 — — ConstantLoss Tangent 5E−4   4E−4  4E−4   4E−4  4E−4 — — Thermal 18 19.9 20.119.4 19.2 — — Conductivity (W/m-K) Roughness 8-16 Same Same Same SameSame Same (μin) Adhesion N/A >28 >28 >28 >28 >28 >28 Over 92% Al₂O₃(MPa) Hermicity <1E−6  1.2E−9 4.4E−10 5.5E−9 9.5E−10 — 1.6E−7 (leakrate) (cm³/s) Hardness 12.14 7.825 8.5 5.009 9.057 — 5.98 (GPa) WearRate 0.2 0.14 0.28 0.113 0.176 — — (nm/RFhr)

Table 1 shows material properties for a substrate of 92% Al₂O₃ (alumina)and for various IAD thin film protective layers coating a substrate of92% Al₂O₃. In the table “C” represents a crystalline structure and “A”represents an amorphous structure. As shown, the alumina substrate has abreakdown voltage of 363 Volts/mil (V/mil). In contrast, a 5 micron (μm)coating of the IAD deposited ceramic compound comprising Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂ has a breakdown voltage of 427 V (much morethan the normalized value of 363 Volts/mil for alumina). A 5 μm coatingof the IAD deposited YAG has a breakdown voltage of 1223 V. A 5 μmcoating of the IAD deposited Er₂O₃ has a breakdown voltage of 527 V. A 5μm coating of the IAD deposited EAG has a breakdown voltage of 900 V. A5 μm coating of the IAD deposited Y₂O₃ has a breakdown voltage of 1032V. A 5 μm coating of the IAD deposited YZ20 has a breakdown voltage of423 V.

A volume resistivity of the alumina is around 0.01×10¹⁶ (0.01E16) Ω·cmat room temperature. A volume resistivity of the ceramic compound thinfilm protective layer is about 4.1E16 Ω·cm at room temperature, and avolume resistivity of the YAG thin film protective layer is about11.3E16 Ω·cm at room temperature.

A dielectric constant of the alumina is about 9.2, a dielectric constantof the ceramic compound thin film is about 9.83, a dielectric constantof the YAG thin film is about 9.76, a dielectric constant of the Er₂O₃thin film is about 9.67, and a dielectric constant of the EAG thin filmis about 9.54. A loss tangent of the alumina is about 5E-4, a losstangent of the ceramic compound thin film is about 4E-4, a loss tangentof the YAG thin film is about 4E-4, a loss tangent of the Er₂O₃ thinfilm is about 4E-4, and a loss tangent of the EAG thin film is about4E-4. A thermal conductivity of the 92% alumina is about 18 W/m-K. Athermal conductivity of a stack of a 5 μm coating of the ceramiccompound thin film over 92% alumina is about 19.9 W/m-K. A thermalconductivity of a stack of a 5 μm coating of the YAG thin film over 92%alumina is about 20.1 W/m-K. A thermal conductivity of a stack of a 5 μmcoating of the Er₂O₃ thin film over 92% alumina is about 19.4 W/m-K. Athermal conductivity of a stack of a 5 μm coating of the EAG thin filmover 92% alumina is about 19.2 W/m-K.

The alumina substrate may have a starting roughness of approximately8-16 micro-inches in one embodiment, and that starting roughness may beapproximately unchanged in all of the thin film protective layers. In anexample, an article with a plasma sprayed coating of the ceramiccompound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂ has arelatively high surface roughness. The surface of the plasma sprayedcoating may have an arithmetic mean waviness (Wa) of 211 microinches(pinch) with a standard deviation (STDEV) of 43, an arithmetic meanroughness (Ra) of 230 pinch with a STDEV of 14, an average length (RSm)of 272 μm with a STDEV of 69, a standard height (Rc) of 19 μm with aSTDEV of 5, and a surface area of 1,726,330 μm² with a STDEV of 37,336.After deposition of a 5 μm thick thin film protective layer of theceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂,each of these roughness metrics may be reduced. In the provided example,Wa is reduced to 187 pinch with a STDEV of 35, Ra is reduced to 191pinch with a STDEV of 30, RSm is reduced to 178 μm with a STDEV of 34,Rc is reduced to 17 μm with a STDEV of 3.7, and the surface area isreduced to 1,695,045 μm² with a STDEV of 258,900. Wa measures an averageabsolute deviation of waviness irregularities. Ra measures averageabsolute deviation of roughness irregularities. Sa measures surface areaof a curve. Rc measures an average value of height in a curve element.RSm measures an average value of the length of a curve element.

Adhesion strength of the thin film protective layers to the aluminasubstrate may be above 28 mega pascals (MPa) for the ceramic compoundthin film and above 32 MPa for the YAG thin film. Adhesion strength maybe determined by measuring the amount of force used to separate the thinfilm protective layer from the substrate. Hermicity measures the sealingcapacity that can be achieved using the thin film protective layer. Asshown, a He leak rate of around 1E-6 cubic centimeters per second(cm³/s) can be achieved using alumina, a He leak rate of around 1.2E-9can be achieved using the ceramic compound, a He leak rate of around4.4E-10 can be achieved using YAG, a He leak rate of around 5.5E-9 canbe achieved using Er₂O₃, a He leak rate of around 1.6E-7 can be achievedusing YZ20, and a He leak rate of around 9.5E-10 can be achieved usingEAG. Lower He leak rates indicate an improved seal. Each of the examplethin film protective layers has a lower He leak rate than typical Al₂O₃.

Each of Y₃Al₅O₁₂, Y₄Al₂O₉, Er₂O₃, Gd₂O₃, Er₃Al₅O₁₂, Gd₃Al₅O₁₂, and theceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂have a high hardness that may resist wear during plasma processing. Asshown, alumina has a Vickers hardness (5 Kgf) of around 12.14 Gigapascals (GPa), the ceramic compound has a hardness of around 7.825 GPa,YAG has a hardness of around 8.5 GPa, Er₂O₃ has a hardness of around5.009 GPa, YZ20 has a hardness of around 5.98 GPa, and EAG has ahardness of around 9.057 GPa, A measured wear rate of alumina is around0.2 nanometers per radio frequency hour (nm/RFhr), a wear rate of theceramic compound is about 0.14 nm/RFhr, a wear rate of Er₂O₃ is about0.113 nm/RFhr, and a wear rate of EAG is about 0.176 nm/RFhr.

Note that the Y₃Al₅O₁₂, Y₄Al₂O₉, Er₂O₃, Gd₂O₃, Er₃Al₅O₁₂, Gd₃Al₅O₁₂, andthe ceramic compound may be modified such that the material propertiesand characteristics identified above may vary by up to 30% in someembodiments. Accordingly, the described values for these materialproperties should be understood as example achievable values. Theceramic thin film protective layers described herein should not beinterpreted as being limited to the provided values.

FIGS. 3A-4C illustrate cross sectional side views of articles (e.g.,chamber components) covered by one or more thin film protective layers.Referring to FIG. 3A, at least a portion of a base or body 305 of anarticle 300 is coated by a thin film protective layer 308. The article300 may be a chamber component, such as a substrate support assembly, anelectrostatic chuck (ESC), a ring (e.g., a process kit ring or singlering), a chamber wall, a base, a gas distribution plate or showerhead, achamber liner, a liner kit, a shield, a plasma screen, a flow equalizer,a cooling base, a chamber viewport, a chamber lid, and so on. The body305 of the article 300 may be a metal, a ceramic, a metal-ceramiccomposite, a polymer, or a polymer-ceramic composite.

Various chamber components are composed of different materials. Forexample, an electrostatic chuck may be composed of a ceramic such asAl₂O₃ (alumina), AlN (aluminum nitride), TiO (titanium oxide), TiN(titanium nitride) or SiC (silicon carbide) bonded to an anodizedaluminum base. Al₂O₃, AlN and anodized aluminum have poor plasma erosionresistance. When exposed to a plasma environment with a Fluorinechemistry and/or reducing chemistry, an electrostatic puck of anelectrostatic chuck may exhibit degraded wafer chucking, increased Heleakage rate, wafer front-side and back-side particle production andon-wafer metal contamination after about 50 radio frequency hours(RFHrs) of processing. A radio frequency hour is an hour of processing.

A lid for a plasma etcher used for conductor etch processes may be asintered ceramic such as Al₂O₃ since Al₂O₃ has a high flexural strengthand high thermal conductivity. However, Al₂O₃ exposed to Fluorinechemistries forms AlF particles as well as aluminum metal contaminationon wafers. Some chamber lids have a thick film protective layer on aplasma facing side to minimize particle generation and metalcontamination and to prolong the life of the lid. However, mostthick-film coatings have inherent cracks and pores that might degradeon-wafer defect performance.

A process kit ring and a single ring are used to seal and/or protectother chamber components, and are typically manufactured from quartz orsilicon. These rings may be disposed around a supported substrate (e.g.,a wafer) to ensure a uniform plasma density (and thus uniform etching).However, quartz and silicon have very high erosion rates under variousetch chemistries (e.g., plasma etch chemistries). Additionally, suchrings may cause particle contamination when exposed to plasmachemistries. The process kit ring and single ring may also consist ofsintered ceramics such as YAG and or ceramic compound comprising Y₄Al₂O₉and a solid-solution of Y₂O₃—ZrO₂.

The showerhead for an etcher used to perform dielectric etch processesis typically made of anodized aluminum bonded to a SiC faceplate. Whensuch a showerhead is exposed to plasma chemistries including fluorine,AlF may form due to plasma interaction with the anodized aluminum base.Additionally, a high erosion rate of the anodized aluminum base may leadto arcing and ultimately reduce a mean time between cleaning for theshowerhead.

A chamber viewport (also known as an endpoint window) is a transparentcomponent typically made of quartz or sapphire. Various optical sensorsmay be protected by the viewport, and may make optical sensor readingsthrough the viewport. Additionally, a viewport may enable a user tovisually inspect or view wafers during processing. Both quartz andsapphire have poor plasma erosion resistance. As the plasma chemistryerodes and roughens the viewport, the optical properties of the viewportchange. For example, the viewport may become cloudy and/or an opticalsignal passing through the viewport may become skewed. This may impairan ability of the optical sensors to collect accurate readings. However,thick film protective layers may be inappropriate for use on theviewport because these coatings may occlude the viewport.

Chamber liners are conventionally made out of an aluminum alloy (e.g.,6061 Aluminum) with a plasma sprayed Yttrium based coating for erosionand corrosion protection. The plasma spray coating is a rough porouscoating with a significant amount of cracking, pores and looseparticles. Process gasses may penetrate the plasma sprayed coating viathe cracks and holes to react with the aluminum alloy. This introducesmetal contamination inside of the chamber. Additionally, the porousplasma sprayed coating may absorb process gasses during processing. Theabsorption of process gasses may occur at the initiation of a process,and may reduce an amount of process gasses that are available forprocessing a first few wafers. This effect is known as the “first wafereffect.” The first wafer effect may be minimized or eliminated byapplying a top coat of a thin film protective layer over the plasmasprayed coating.

The examples provided above set forth just a few chamber componentswhose performance may be improved by use of a thin film protective layeras set forth in embodiments herein.

Referring back to FIG. 3A, a body 305 of the article 300 may include oneor more surface features, such as the mesa illustrated in FIG. 3A. Foran electrostatic chuck, surface features may include mesas, sealingbands, gas channels, helium holes, and so forth. For a showerhead,surface features may include a bond line, hundreds or thousands of holesfor gas distribution, divots or bumps around gas distribution holes, andso forth. Other chamber components may have other surface features.

The thin film protective layer 308 formed on the body 305 may conform tothe surface features of the body 305. As shown, the thin film protectivelayer 308 maintains a relative shape of the upper surface of the body305 (e.g., telegraphing the shapes of the mesa). Additionally, the thinfilm coating may be thin enough so as not to plug holes in theshowerhead or He holes in the electrostatic chuck. In one embodiment,the thin film protective layer 308 has a thickness of below about 1000microns. In one embodiment, the thin film protective layer 308 has athickness of below about 50 microns. In a further embodiment, the thinfilm protective layer has a thickness of below about 20 microns. In afurther embodiment, the thin film protective layer has a thickness ofbetween about 0.5 microns to about 7 microns.

The thin film protective layer 308 is a deposited ceramic layer that maybe formed on the body 305 of the article 300 using an ion assisteddeposition (IAD) process or a physical vapor deposition (PVD) process.The IAD or PVD deposited thin film protective layer 308 may have arelatively low film stress (e.g., as compared to a film stress caused byplasma spraying or sputtering). The relatively low film stress may causethe lower surface of the body 305 to be very flat, with a curvature ofless than about 50 microns over the entire body for a body with a 12inch diameter. The IAD or PVD deposited thin film protective layer 308may additionally have a porosity that is less than 1%, and less thanabout 0.1% in some embodiments. Therefore, the IAD or PVD depositedprotective layer is a dense structure, which can have performancebenefits for application on a chamber component. Additionally, the IADor PVD deposited protective layer 308 may be deposited without firstroughening the upper surface of the body 305 or performing other timeconsuming surface preparation steps. Since roughening the body mayreduce a breakdown voltage of the body 305, the ability to apply thethin film protective layer 308 without first roughening the body 305 maybe beneficial for some applications (e.g., for an electrostatic chuck).

FIG. 3B illustrates a cross sectional side view of one embodiment of anarticle 350 having a body 355 coated by a thin film protective layer358. As shown, the body 355 may be devoid of features. In oneembodiment, the body 355 is polished prior to deposition of the thinfilm protective layer 358. Rather than having features in the body 355,features may be formed in the thin film protective layer 358. Forexample, the thin film protective layer 358 may be masked and thenetched or bead blasted to remove unmasked portions of the thin filmprotective layer 358. The features can also be formed by masking thesubstrate and then applying the thin coating. Formed features mayinclude mesas, channels, seal rings, exposed bond lines (e.g., of ashowerhead), and so forth. Additionally, holes may be drilled in thethin film protective layer, such as by laser drilling. If features areto be formed in the thin film protective layer 358, the thin filmprotective layer should preferably have a thickness that is great enoughto accommodate the features. For example, if 12 μm mesas are to beformed in the thin film protective layer, then the thin film protectivelayer 358 should have a thickness that is greater than 12 μm. In otherembodiments, some features may be formed in the body 355, and otherfeatures may be formed in the thin film protective layer 358.

FIG. 4A illustrates a cross sectional side view of one embodiment of anarticle 400 having a thick protective layer 410 and a thin filmprotective layer 415 coating at least one surface of a body 405. Thethick protective layer 410 may be a Y₃Al₅O₁₂, Y₄Al₂O₉, Y₂O₃, or theceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.Other plasma resistant ceramics may also be used for the thickprotective layer 410.

The thick protective layer 410 may be a thick film protective layer,which may have been thermally sprayed (e.g., plasma sprayed) onto thebody 405. An upper surface of the body 405 may be roughened prior toplasma spraying the thick film protective layer onto it. The rougheningmay be performed, for example, by bead blasting the body 405. Rougheningthe upper surface of the body provides anchor points to create amechanical bond between the plasma sprayed thick film protective layerand the body 405 for better adhesion. The thick film protective layermay have an as sprayed thickness of up to about 200 microns or thicker,and may be ground down to a final thickness of approximately 50 micronsin some embodiments. A plasma sprayed thick film protective layer mayhave a porosity of about 2-4%.

Alternatively, the thick protective layer 410 may be a bulk sinteredceramic that has been bonded to the body 405. The thick protective layer410 may be provided, for example, as a thin ceramic wafer having athickness of approximately 200 microns.

The thin film protective layer 415 may be applied over the thickprotective layer 410 using IAD or PVD. The thin film protective layer415 may act as a top coat, and may act as an erosion resistant barrierand seal an exposed surface of the thick protective layer 410 (e.g.,seal inherent surface cracks and pores in the thick protective layer410).

FIG. 4B illustrates a cross sectional side view of one embodiment of anarticle 420 having a thin film protective layer stack 438 deposited overa body 425 of the article 420. Each thin film protective layer 430, 435in the thin film protective layer stack 438 may be one of the ceramicmaterials described above. In one embodiment, the same ceramic materialis not used for two adjacent thin film protective layers. However, inanother embodiment adjacent layers may be composed of the same ceramic.

FIG. 4C illustrates a cross sectional side view of another embodiment ofan article 440 having a thick protective layer 450 and a thin filmprotective layer stack 470 deposited over the thick protective layer450.

The thin film protective layer stacks (such as those illustrated) mayhave any number of thin film protective layers. The thin film protectivelayers in a stack may all have the same thickness, or they may havevarying thicknesses. Each of the thin film protective layers may have athickness of less than approximately 20 microns, and less thanapproximately 10 microns in some embodiments. In one example, a firstlayer 430 may have a thickness of 4 microns, and a second layer 435 mayhave a thickness of 1 micron. If the first layer is amorphous and thesecond layer is crystalline, then such a bi-layer architecture mayreduce cracking probability while providing enhanced erosion resistance.In another example, first layer 455 may be a YAG layer having athickness of 2 microns, second layer 460 may be a compound ceramic layerhaving a thickness of 1 micron, and third layer 465 may be a YAG layerhaving a thickness of 1 micron.

The selection of the number of ceramic layers and the composition of theceramic layers to use may be based on a desired application and/or atype of article being coated. EAG and YAG thin film protective layersformed by IAD and PVD typically have an amorphous structure. Incontrast, the IAD and PVD deposited compound ceramic and Er₂O₃ layerstypically have a crystalline or nano-crystalline structure. Crystallineand nano-crystalline ceramic layers may generally be more erosionresistant than amorphous ceramic layers. However, in some instances thinfilm ceramic layers having a crystalline structure or nano-crystallinestructure may experience occasional vertical cracks (cracks that runapproximately in the direction of the film thickness and approximatelyperpendicular to the coated surface). Such vertical cracks may be causedby lattice mismatch and may be points of attack for plasma chemistries.Each time the article is heated and cooled, the mismatch in coefficientsof thermal expansion between the thin film protective layer and thesubstrate that it coats cause stress on the thin film protective layer.Such stress may be concentrated at the vertical cracks. This may causethe thin film protective layer to eventually peel away from thesubstrate that it coats. In contrast, if there are not vertical cracks,then the stress is approximately evenly distributed across the thinfilm. Accordingly, in one embodiment a first layer 430 in the thin filmprotective layer stack 438 is an amorphous ceramic such as YAG or EAG,and the second layer 435 in the thin film protective layer stack 438 isa crystalline or nano-crystalline ceramic such as the ceramic compoundor Er₂O₃. In such an embodiment, the second layer 435 may providegreater plasma resistance as compared to the first layer 430. By formingthe second layer 435 over the first layer 430 rather than directly overthe body 425, the first layer 430 acts as a buffer to minimize latticemismatch on the subsequent layer. Thus, a lifetime of the second layer435 may be increased.

In another example, each of the body, Y₃Al₅O₁₂ (YAG), Y₄Al₂O₉, Er₂O₃,Gd₂O₃, Er₃Al₅O₁₂, Gd₃Al₅O₁₂, and the ceramic compound comprising Y₄Al₂O₉and a solid-solution of Y₂O₃—ZrO₂ may have a different coefficient ofthermal expansion. The greater the mismatch in the coefficient ofthermal expansion between two adjacent materials, the greater thelikelihood that one of those materials will eventually crack, peel away,or otherwise lose its bond to the other material. The protective layerstacks 438, 470 may be formed in such a way to minimize mismatch of thecoefficient of thermal expansion between adjacent layers (or between alayer and a body 425, 445). For example, thick protective layer 450 maybe alumina, and EAG may have a coefficient of thermal expansion that isclosest to that of alumina, followed by the coefficient of thermalexpansion for YAG, followed by the coefficient of thermal expansion forthe compound ceramic. Accordingly, first layer 455 may be EAG, secondlayer 460 may be YAG, and third layer 465 may be the compound ceramic inone embodiment.

In another example, the layers in the protective layer stack 470 may bealternating layers of two different ceramics. For example, first layer455 and third layer 465 may be YAG, and second layer 460 and a fourthlayer (not illustrated) may be the compound ceramic. Such alternatinglayers may provide advantages similar to those set forth above in caseswhere one material used in the alternating layers is amorphous and theother material used in the alternating layers is crystalline ornano-crystalline.

In some embodiments, one of more of the layers in the thin filmprotective layer stacks 438, 470 are transition layers formed using aheat treatment. If the body 425, 445 is a ceramic body, then a hightemperature heat treatment may be performed to promote interdiffusionbetween a thin film protective layer and the body. Additionally, theheat treatment may be performed to promote interdiffusion betweenadjacent thin film protective layers or between a thick protective layerand a thin film protective layer. Notably, the transition layer may be anon-porous layer. The transition layer may act as a diffusion bondbetween two ceramics, and may provide improved adhesion between theadjacent ceramics. This may help prevent a protective layer fromcracking, peeling off, or stripping off during plasma processing.

The thermal treatment may be a heat treatment at up to about 1400-1600degrees C. for a duration of up to about 24 hours (e.g., 3-6 hours inone embodiment). This may create an inter-diffusion layer between afirst thin film protective layer and one or more of an adjacent ceramicbody, thick protective layer or second thin film protective layer. Ifthe ceramic body is Al₂O₃, and the protective layer is composed of acompound ceramic Y₄Al₂O₉ (YAM) and a solid solution Y₂-xZr_(x)O₃(Y₂O₃—ZrO₂ solid solution), then a Y₃Al₅O₁₂ (YAG) interface layer willbe formed. Similarly, a heat treatment will cause a transition layer ofEAG to form between Er₂O₃ and Al₂O₃. A heat treatment will also cause atransition layer of YAG to form between Y₂O₃ and Al₂O₃. A heat treatmentmay also cause GAG to form between Gd₂O₃ and Al₂O₃. A heat treatment ofyttria stabilized zirconia (YSZ) over Al₂O₃ can form a transition layerof the compound ceramic of Y₄Al₂O₉ (YAM) and a solid solutionY₂-xZr_(x)O₃. Other transition layers may be formed between otheradjacent ceramics.

In one embodiment, a coloring agent is added during the deposition ofthe first protective layer 308, 408. Accordingly, when the secondprotective layer 310, 410 wears away, an operator may have a visualqueue that it is time to refurbish or exchange the lid or nozzle.

FIG. 5 illustrates a chamber liner 500 having a hollow cylindrical body505. The hollow cylindrical body 505 may be Aluminum or an Aluminumalloy in one embodiment. The hollow cylindrical body 505 has a plasmasprayed Yttrium based plasma resistant layer 510 coating an innersurface of the body 505. The plasma sprayed Yttrium based plasmaresistant layer 510 may have numerous cracks and pores. For example, theplasma sprayed Yttrium based plasma resistant layer 510 may have aporosity of approximately 2-4% in one embodiment. The chamber liner 500further includes a thin film protective layer 515 coating the plasmasprayed Yttrium based plasma resistant layer 510. The thin filmprotective layer 515 may be composed of a plasma resistant rare earthoxide, such as those discussed herein above. The thin film protectivelayer 515 may be conformal and dense, with a porosity of less than 1%.In one embodiment, the porosity is effectively 0% (e.g., less than0.1%). The thin film protective layer 515 may seal the cracks and poresof the plasma sprayed Yttrium based plasma resistant layer 510.

The chamber liner 500 has a first side 520 and a second side 525. Thethin film protective layer 515 may be deposited by IAD or PVD inmultiple passes. In one embodiment, a target material and electron beamgun are positioned at the first side 520 initially during the depositionprocess. The chamber liner 500 may be rotated during the process to coatthe some or all off the inner surface of the chamber liner 500. Regionsof the chamber liner 500 that are closer to the first side 520 may becloser to the target material and gun, and may thus receive a thickerdeposited thin film protective layer 515 than regions that are far fromthe first side. Accordingly, the chamber liner 500 may be repositionedso that the target material and electron beam gun are positioned at thesecond side 525 of the chamber liner 500 during a second portion of thedeposition process. This may ensure that all regions of the chamberliner's inner surface receive a relatively uniform coating.

Some locations of the chamber liner 500 may be more prone to erosionthan other areas. In one embodiment, the chamber liner 500 is maskedbefore deposition of the thin film protective layer 515. The mask maycover regions that are less prone to erosion and expose those regionsthat are more prone to erosion. Accordingly, the deposited thin filmprotective layer 515 may cover those regions that experience highererosion rates without covering those regions that experience lowererosion rates.

FIG. 6A illustrates one embodiment of a process 600 for forming a thinfilm protective layer over a body of an article such as a chambercomponent. At block 605 of process 600, an article is provided. At block610, a determination is made of whether or not to deposit a thick filmprotective layer onto the article. If a thick film protective layer isto be formed, the method proceeds to block 615. Otherwise, the methodcontinues to block 620.

At block 615, a thermal spray process (e.g., a plasma spray process) isperformed to deposit a thick film protective layer onto the article.Prior to performing the thermal spray process, the body of the articlemay be roughened in some embodiments. The thick film protective layermay be any plasma resistant ceramic. Some examples of thick filmprotective layers include Y₃Al₆O₁₂, Y₄Al₂O₉, Y₂O₃, YSZ, or the ceramiccompound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂. After thethick film protective layer is formed, for some applications surfacefeatures are formed on a surface of the thick film protective layer. Forexample, if the article is an ESC, then mesas and He holes may beformed. In an alternative embodiment, a plasma resistant ceramic disc orother ceramic structure may be bonded to the body of the article ratherthan spraying a thick film protective layer.

At block 620, IAD or PVD is performed to deposit a thin film protectivelayer on the body of the article. If a thick film protective layer wasformed at block 615, then the thin film protective layer may be formedover the thick film protective layer as a top coat. In one embodiment,chamber surface preparation is performed prior to performing IAD todeposit the thin film protective layer. For example, ion guns canprepare a surface of the article by using Oxygen and/or Argon ions toburn surface organic contamination and disperse remaining surfaceparticles.

The thin film protective layer may be Y₃Al₆O₁₂, Y₄Al₂O₉, Er₂O₃, Gd₂O₃,Er₃Al₆O₁₂, Gd₃Al₆O₁₂, the ceramic compound of Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂, or any of the other plasma resistantceramics described herein. A deposition rate for the thin filmprotective layer may be about 0.25-10 Angstroms per second (A/s), andmay be varied by tuning deposition parameters. In one embodiment,multiple deposition rates are used during deposition of the thin filmprotective layer. For example, an initial deposition rate of 0.25-1.0A/s may be used to achieve a conforming and well adhering coating. Thedeposition rate may then be increased to 2-10 A/s to achieve a thickercoating in a shorter and more cost effective coating run. The thin filmprotective layers may be very conforming, may be uniform in thickness,and have a good adhesion to the body/substrate that they are depositedon.

In one embodiment, the article is cooled during deposition of the thinfilm protective layer to maintain a temperature of the article at orbelow approximately 150° C. In one embodiment, a working distancebetween a target material and the article is set to less than one meter.

In one embodiment, the article is a chamber liner of an etch reactor,where the chamber liner has a hollow cylindrical shape. Performing theIAD process may include placing the article in a first position suchthat a target is at a first opening of the article. A first portion ofthe interior of the article may be coated while the article is in thefirst position. The article may then be placed in a second position suchthat the target is at a second opening of the article. A second portionof the interior of the article may be coating while the article is inthe second position.

In one embodiment, one or more regions of the article that will exhibita high erosion rate relative to other regions of the article areidentified. The article is then masked with a mask that exposed theidentified one or more regions. The IAD deposition is then performed toform the thin film protective layer at the identified one or moreregions.

At block 625, a determination is made regarding whether to deposit anyadditional thin film protective layers. If an additional thin filmprotective layer is to be deposited, the process continues to block 630.At block 630, another thin film protective layer is formed over thefirst thin film protective layer. The other thin film protective layermay be composed of a ceramic that is different than a ceramic of thefirst thin film protective layer. In one embodiment, the other thin filmprotective layer is one of Y₃Al₆O₁₂, Y₄Al₂O₉, Er₂O₃, Gd₂O₃, Er₃Al₆O₁₂,Gd₃Al₆O₁₂, the ceramic compound of Y₄Al₂O₉ and a solid-solution ofY₂O₃—ZrO₂, or any of the other ceramic materials described herein. Themethod then returns to block 625. If at block 625 no additional thinfilm protective layers are to be applied, the process ends. After any ofthe thin film protective layers is deposited, surface features may beformed in that thin film protective layer.

FIG. 6B illustrates one embodiment of a process 650 for forming a thinfilm protective layer over a body of an article using IAD or PVD with ametallic target. At block 655 of process 600, an article is provided ina deposition chamber. At block 660, Nitrogen or Oxygen radicals areflowed into the deposition chamber at a flow rate. At block 665,Nitrogen or Oxygen ions are used to bombard the article. At block 670,IAD or PVD is performed with a metallic target to deposit a thin filmprotective layer on the article. An electron beam vaporizes or sputtersthe metallic target, which reacts with the Nitrogen or Oxygen radicalsand/or ions to form a ceramic in situ. If nitrogen radicals and/or ionsare used, then the ceramic will be a nitride. If Oxygen radicals and/orions are used, then the ceramic will be an oxide.

At block 675, a determination is made of whether to increase the Oxygenor Nitrogen content in the thin film protective layer. If the Oxygen orNitrogen content is to be increased, the process continues to block 680.At block 680, the flow of Oxygen radicals or Nitrogen radicals may beincreased. Alternatively or additionally, the bombardment by Oxygen ionsor Nitrogen ions may be increased. The process then returns to block670. If at block 675 a determination is made not to increase the Oxygenor Nitrogen content in the thin film protective layer, the processproceeds to block 685.

At block 685, a determination is made of whether the thin filmprotective layer has reached a desired thickness. If a desired thicknesshas been reached, the process terminates. If a desired thickness has notbeen reached, the process returns to block 670.

With IAD processes, the energetic particles may be controlled by theenergetic ion (or other particle) source independently of otherdeposition parameters. According to the energy (e.g., velocity), densityand incident angle of the energetic ion flux, composition, structure,crystalline orientation and grain size of the thin film protective layermay be manipulated. Additional parameters that may be adjusted are atemperature of the article during deposition as well as the duration ofthe deposition. The ion energy may be roughly categorized into lowenergy ion assist and high energy ion assist. Low energy ion assist mayinclude a voltage of about 230V and a current of about 5 A. High energyion assist may include a voltage of about 270V and a current of about 7A. The low and high energy for the ion assist is not limited to thevalues mentioned herein. The high and low level designation mayadditionally depend on the type of the ions used and/or the geometry ofthe chamber used to perform the IAD process. The ions are projected witha higher velocity with high energy ion assist than with low energy ionassist. Substrate (article) temperature during deposition may be roughlydivided into low temperature (around 120-150° C. in one embodiment whichis typical room temperature) and high temperature (around 270° C. in oneembodiment). For high temperature IAD deposition processes, the articlemay be heated prior to and during deposition.

TABLE 2A Example Thin Film Protective Layers Formed Using IAD Thk. Dep.Rate Ion Temp. Vacuum Hardness Material (μm) (A/s) Assist (° C.) XRD(cm³/s) (GPa) 1^(st) Compound Ceramic 5 2 230 V, 270 C N/A 4.11(sintered plug) 5 A 2^(nd) Compound Ceramic 6 1 for 2 μm 230 V, 270 C +A 5.0E−6 (sintered plug) 2 for 4 μm 5 A 3^(rd) Compound Ceramic 5 1 230V, 270 C + A 6.3E−6 (sintered plug) 5 A 4^(th) Compound Ceramic 5 1 for1 μm 270 V, 270 A 1.2E−9 7.825 (sintered plug) 2 for 4 μm 7 A 5^(th)Compound Ceramic 5 1 for 1 μm 270 V, 120-150 A 1.2E−9 (calcined powder)2 for 4 μm 7 A 6^(th) Compound Ceramic 5 1 for 1 μm 270 V, 120-150 A1.2E−9 7.812 (calcined powder) 4 for 4 μm 7 A 1^(st) YAG 5 2.5 230 V,270 A 3.7E−7 5.7 (fused lump) 5 A 2^(nd) YAG (fused lump) 5 1 for 1 μm270 V, 270 A 4.4E−10 8.5 2 for 4 μm 7 A Compound Ceramic/YAG 5 2 230 V,270 C + A 3.7E−7 5 A 1^(st) Er₂O₃ (sintered lump) 5 2 230 V, 270 C  3E−6 5 A 2^(nd) Er₂O₃ (sintered lump) 5 1 for 1 μm 270 V, 270 C 5.5E−95.009 2 for 4 μm 7 A

TABLE 2B Example Thin Film Protective Layers Formed Using IAD Thk. Dep.Rate Ion Temp. Vacuum Hardness Material (μm) (A/s) Assist (° C.) XRD(cm³/s) (GPa) 1^(st) EAG 7.5 1 for 1 μm 270 V, 270 A 9.5E−10 8.485(calcined powder) 2 for next 7 A 2^(nd) EAG (calcined power) 7.5 1 for 1μm 270 V, 120-150 A 2.5E−9 9.057 2 for next 7A 3^(rd) EAG (calcined 5 1for 1 μm 270 V, A powder) 2 for 4 μm 7 A Y₂O₃ (fused lump) 5 1 for 1 μm270 V, 270 C 2 for 4 μm 7 A YZ20 (Powder) 5 1 for 1 μm 270 V, 120-150 C1.6E−7 5.98 2 for 4 μm 7 A

Tables 2A-2B show multiple example thin film protective layers formedusing IAD with various deposition parameters. The experimental resultsidentify an optimized coating process based on a multi-factorial designof experiments (DOE) that varies ion assisted energy, deposition rateand temperature to obtain a conforming, dense microstructure. Thecoatings are characterized in terms of material properties(microstructure and/or crystal phase) and mechanical properties(hardness and adhesion), as well as crack density and vacuum sealingcapability. IAD coating process optimization can produce IAD coatingswith high density thin-films with low residual stress. The optimizedparameters can be used for most rare earth oxide based coatingmaterials.

Six different examples are shown for thin film protective layers formedfrom the ceramic compound of Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.A first example compound ceramic thin film protective layer has athickness of 5 microns, and was formed using IAD with a low energy ionassist and a sintered plug target, a deposition temperature of 270° C.,and a deposition rate of 2 angstroms per seconds (A/s). X-raydiffraction showed that the first example compound ceramic thin filmprotective layer had a crystalline structure. The first example compoundceramic thin film protective layer also had a hardness of 4.11 GPa andvisual inspection showed good conformance to the underlying substrate aswell as some vertical cracks and some spikes.

A second example compound ceramic thin film protective layer has athickness of 6 microns, and was formed using IAD with a low energy ionassist and a sintered plug target, a deposition temperature of 270° C.,and a deposition rate of 1 A/s for the first 2 microns and a depositionrate of 2 A/s for the subsequent 4 microns. X-ray diffraction showedthat the second example compound ceramic thin film protective layer hada nano-crystalline structure (in which portions are crystalline andportions are amorphous). When used as a seal, the second examplecompound ceramic thin film protective layer was able to maintain avacuum down to 5E-6 cubic centimeters per second (cm³/s). Visualinspection of the second example compound ceramic thin film protectivelayer showed good conformance and fewer vertical cracks than the firstexample compound ceramic thin film protective layer.

A third example compound ceramic thin film protective layer has athickness of 5 microns, and was formed using IAD with a low energy ionassist and a sintered plug target, a deposition temperature of 270° C.,and a deposition rate of 1 A/s. X-ray diffraction showed that the thirdexample compound ceramic thin film protective layer had anano-crystalline structure. When used as a seal, the third examplecompound ceramic thin film protective layer was able to maintain avacuum down to 6.3E-6 cm³/s. Visual inspection of the third examplecompound ceramic thin film protective layer showed good conformance andfewer vertical cracks than the first example compound ceramic thin filmprotective layer.

A fourth example compound ceramic thin film protective layer has athickness of 5 microns, and was formed using IAD with a high energy ionassist and a sintered plug target, a deposition temperature of 270° C.,and a deposition rate of 1 A/s for the first micron and 2 A/s for thesubsequent 4 microns. X-ray diffraction showed that the third examplecompound ceramic thin film protective layer had an approximatelyamorphous structure. When used as a seal, the third example compoundceramic thin film protective layer was able to maintain a vacuum down to1.2E-9 cm³/s. Visual inspection of the fourth example compound ceramicthin film protective layer showed good conformance, a smooth surface andvery few vertical cracks. Additionally, the fourth example compoundceramic thin film protective layer has a hardness of 7.825 GPa.

A fifth example compound thin film protective layer was formed using thesame parameters as the fourth example compound thin film protectivelayer, but with a deposition temperature at room temperature (around120-150° C.) and with a calcined powder target. The fifth examplecompound thin film protective layer showed similar properties to thoseof the fourth example compound thin film protective layer.

A sixth example compound ceramic thin film protective layer has athickness of 5 microns, and was formed using IAD with a high energy ionassist and a calcined powder target, a deposition temperature of 270°C., and a deposition rate of 1 A/s for the first micron and 4 A/s forthe subsequent 4 microns. X-ray diffraction showed that the thirdexample compound ceramic thin film protective layer had an approximatelyamorphous structure. When used as a seal, the third example compoundceramic thin film protective layer was able to maintain a vacuum down to1.2E-9 cm³/s. The fourth example compound ceramic thin film protectivelayer has a hardness of 7.812 GPa.

A first example YAG thin film protective layer has a thickness of 5microns, and was formed using IAD with a low energy ion assist and afused lump target, a deposition temperature of 270° C., and a depositionrate of 2.5 A/s. X-ray diffraction showed that the first YAG ceramicthin film protective layer had an amorphous structure. The first YAGthin film protective layer also had a hardness of 5.7 GPa and visualinspection showed good conformance, minimal cracking and a smoothsurface.

A second example YAG thin film protective layer has a thickness of 5microns, and was formed using IAD with a high energy ion assist and afused lump target, a deposition temperature of 270° C., and a depositionrate of 1 A/s for a first micron and 2 A/s for the subsequent 4 microns.X-ray diffraction showed that the second YAG thin film protective layerhad an amorphous structure. The second YAG thin film protective layeralso had a hardness of 8.5 GPa and visual inspection showed goodconformance, reduced cracking compared to the first YAG thin film and asmooth surface.

An example thin film protective layer stack with alternating compoundceramic and YAG layers has a thickness of 5 microns, and was formedusing IAD with a low energy ion assist, a deposition temperature of 270°C., and a deposition rate of 2 A/s. X-ray diffraction showed that thealternating layers were amorphous (for the YAG layers) and crystallineor nano-crystalline (for the compound ceramic layers). Visual inspectionshowed reduced vertical cracks for the compound ceramic layers.

A first example Er₂O₃ thin film protective layer has a thickness of 5microns, and was formed using IAD with a low energy ion assist and asintered lump target, a deposition temperature of 270° C., and adeposition rate of 2 A/s. X-ray diffraction showed that the first Er₂O₃ceramic thin film protective layer had a crystalline structure. Visualinspection showed good conformance and a vertical cracking.

A second example Er₂O₃ thin film protective layer has a thickness of 5microns, and was formed using IAD with a high energy ion assist and asintered lump target, a deposition temperature of 270° C., and adeposition rate of 1 A/s for the first micron and a deposition rate of 2A/s for the subsequent 4 microns. X-ray diffraction showed that thesecond Er₂O₃ ceramic thin film protective layer had a crystallinestructure. Visual inspection showed good conformance and a less verticalcracking compared to the first Er₂O₃ ceramic thin film protective layer.

A first example EAG thin film protective layer has a thickness of 7.5microns, and was formed using IAD with a high energy ion assist and acalcined powder target, a deposition temperature of 270° C., and adeposition rate of 1 A/s for the first micron and a deposition rate of 2A/s for the subsequent microns. X-ray diffraction showed that the firstEAG ceramic thin film protective layer had an amorphous structure, andthe layer had a hardness of 8.485 GPa. Visual inspection showed goodconformance and minimal cracking.

A second example EAG thin film protective layer has a thickness of 7.5microns, and was formed using IAD with a high energy ion assist and acalcined powder target, a deposition temperature of 120-150° C., and adeposition rate of 1 A/s for the first micron and a deposition rate of 2A/s for the subsequent microns. X-ray diffraction showed that the secondEAG ceramic thin film protective layer had an amorphous structure, andthe layer had a hardness of 9.057 GPa. Visual inspection showed goodconformance and a less cracking compared to the first EAG ceramic thinfilm protective layer.

A third example EAG thin film protective layer has a thickness of 5microns, and was formed using IAD with a high energy ion assist and acalcined powder target, and a deposition rate of 1 A/s for the firstmicron and a deposition rate of 2 A/s for the subsequent microns. X-raydiffraction showed that the third EAG ceramic thin film protective layerhad an amorphous structure.

An example Y₂O₃ thin film protective layer has a thickness of 5 microns,and was formed using IAD with a high energy ion assist and a fused lumptarget, a temperature of 270° C., and a deposition rate of 1 A/s for thefirst micron and a deposition rate of 2 A/s for the subsequent microns.X-ray diffraction showed that the third EAG ceramic thin film protectivelayer had a crystalline structure.

An example YZ20 thin film protective layer has a thickness of 5 microns,and was formed using IAD with a high energy ion assist and a powdertarget, a temperature of 120-150° C., and a deposition rate of 1 A/s forthe first micron and a deposition rate of 2 A/s for the subsequentmicrons. X-ray diffraction showed that the YZ20 ceramic thin filmprotective layer had a crystalline structure. When used as a seal, theYZ20 ceramic thin film protective layer was able to maintain a vacuumdown to 1.6E-7 cm³/s. The YZ20 ceramic thin film protective layer had ahardness of 5.98 GPa.

FIGS. 7A-7E illustrate scanning electron microscope (SEM) images ofarticles having a thin film protective layer formed from the ceramiccompound of Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂ deposited over aplasma sprayed protective layer also formed from the ceramic compound ofY₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂. FIG. 7A shows a top down SEMimage of a flat region of an article that has been coated with theplasma sprayed layer. The SEM image of FIG. 7A has a magnification ofapproximately 10,000 and a view field of approximately 22 μm. The plasmasprayed layer includes multiple cracks, such as crack 710. FIG. 7B showsa top down SEM image of a flat region of the article after the thin filmprotective layer has been deposited over the plasma sprayed layer. TheSEM image of FIG. 7B has a magnification of approximately 10,000 and aview field of approximately 23 μm. The thin film protective layer hassealed the cracks in the plasma sprayed layer. A sealed crack 715 isshown.

FIG. 7C shows a cross sectional side view SEM image of a flat region ofan article with a thin film protective layer 725 coating a plasmasprayed protective layer 720. The SEM image of FIG. 7C has amagnification of approximately 10,000 and a view field of approximately23 μm. FIG. 7D shows a cross sectional side view SEM image of ahorizontal grating region of an article with a thin film protectivelayer 735 coating a plasma sprayed protective layer 730. The SEM imageof FIG. 7D has a magnification of approximately 10,000 and a view fieldof approximately 23 μm. FIG. 7E shows a cross sectional side view SEMimage of a vertical grating region of an article with a thin filmprotective layer 745 coating a plasma sprayed protective layer 740. TheSEM image of FIG. 7E has a magnification of approximately 4,000 and aview field of approximately 56 μm.

As shown in the SEM images of FIGS. 7A-7E, the thin film protectivelayer conforms to the surface of the plasma sprayed protective layer.Additionally, the thin film protective layer seals cracks and pores inthe plasma sprayed protective layer in flat regions, horizontal gratingregions and vertical grating regions.

Sample erosion rates of various materials exposed to dielectric etch CF₄chemistry, including erosion rates of multiple different IAD coatingsgenerated in accordance with embodiments, are now described. An erosionrate of 92% alumina is around 1.38 microns per radiofrequency hour(μm/Rfhr). An erosion rate of 99.8% alumina is around 1.21 μm/Rfhr. Anerosion rate of IAD deposited YAG is around 0.28 μm/Rfhr. An erosionrate of IAD deposited EAG is about 0.24 μm/Rfhr. An erosion rate of IADdeposited Y₂O₃ is about 0.18 μm/Rfhr. An erosion rate of IAD depositedEr2O3 is about 0.18 μm/Rfhr. An erosion rate of the IAD depositedcompound ceramic is about 0.18 μm/Rfhr. A radiofrequency hour is an hourof processing.

FIGS. 8-9 illustrate erosion rates for thin film protective layersformed in accordance with embodiments of the present invention. FIG. 8shows erosion rates of thin film protective layers when exposed to aCH₄/Cl₂ plasma chemistry. As shown, the IAD deposited thin filmprotective layers show a much improved erosion resistance as compared toAl₂O₃. For example, alumina with a 92% purity showed an erosion rate ofaround 18 nanometers pre radiofrequency hour (nm/RFHr) and alumina witha 99.8% purity showed an erosion rate of about 56 nm/RFHr. In contrastan IAD deposited compound ceramic thin film protective layer showed anerosion rate of about 3 nm/RFHr and an IAD deposited YAG thin filmprotective layer showed an erosion rate of about 1 nm/RFHr.

FIG. 9 shows erosion rates of thin film protective layers when exposedto a H₂/NF₃ plasma chemistry. As shown, the IAD deposited thin filmprotective layers show a much improved erosion resistance as compared toAl₂O₃. For example, alumina with a 92% purity showed an erosion rate ofaround 190 nm/RFHr and alumina with a 99.8% purity showed an erosionrate of about 165 nm/RFHr. In contrast an IAD deposited YAG thin filmprotective layer showed an erosion rate of about 52 nm/RFHr. Similarly,a compound ceramic thin film protective layer deposited using IAD withlow energy ions showed an erosion rate of about 45 nm/RFHr and acompound ceramic thin film protective layer deposited using IAD withhigh energy ions showed an erosion rate of about 35 nm/RFHr. An EAG thinfilm protective layer deposited using IAD with high depositiontemperature (e.g., around 270° C.) showed an erosion rate of about 95nm/RFHr and an EAG thin film protective layer deposited using IAD withlow deposition temperature (e.g., around 120-150° C.) showed an erosionrate of about 70 nm/RFHr. An Er₂O₃ thin film protective layer depositedusing IAD with high energy ions showed an erosion rate of about 35nm/RFHr.

FIGS. 10-11 illustrate roughness profiles for thin film protectivelayers formed in accordance with embodiments of the present invention.FIG. 10 shows surface roughness profiles of thin film protective layersof FIG. 8 before and after exposure to a CH₄/Cl₂ plasma chemistry for100 RFHrs. As shown, the IAD deposited thin film protective layers showa minimum change in surface roughness after exposure to a CH₄/Cl₂ plasmachemistry for 100 RFHrs.

FIG. 11 shows surface roughness profiles of thin film protective layersof FIG. 9 before and after exposure to an H₂/NF₃ plasma chemistry for 35RFHrs. As shown, the IAD deposited thin film protective layers show aminimum change in surface roughness after exposure to an H₂/NF₃ plasmachemistry for 35 RFHrs.

Erosion rates of various materials exposed to a CF₄—CHF₃ trenchchemistry at low bias are now briefly discussed. An erosion rate of 92%Alumina is around 0.26 microns per radiofrequency hour (μm/Rfhr), anerosion rate of IAD deposited EAG is around 0.18 μm/Rfhr, an erosionrate of IAD deposited YAG is about 0.15 μm/Rfhr, an erosion rate of theplasma spray deposited compound ceramic is about 0.09 μm/Rfhr, anerosion rate of IAD deposited Y₂O₃ is about 0.08 μm/Rfhr, an erosionrate of IAD deposited ceramic compound is about 0.07 μm/Rfhr, an erosionrate of bulk Y₂O₃ is about 0.07 μm/Rfhr, an erosion rate of a bulkceramic compound is about 0.065 μm/Rfhr, and an erosion rate of IADdeposited Er₂O₃ is about 0.05 μm/Rfhr. Similar etch results occur whenthese materials are etched using a CF₄—CHF₃ trench chemistry at a highbias. For example, at a high bias an etch rate of 92% Alumina is around1.38 μm/Rfhr, an erosion rate of IAD deposited EAG is around 0.27μm/Rfhr, an erosion rate of IAD deposited YAG is about 0.27 μm/Rfhr, anerosion rate of the plasma spray deposited compound ceramic is about0.35 μm/Rfhr, an erosion rate of IAD deposited Y₂O₃ is about 0.18μm/Rfhr, an erosion rate of IAD deposited ceramic compound is about 0.19μm/Rfhr, an erosion rate of bulk Y₂O₃ is about 0.4 μm/Rfhr, an erosionrate of a bulk ceramic compound is about 0.4 μm/Rfhr, and an erosionrate of IAD deposited Er₂O₃ is about 0.18 μm/Rfhr.

The preceding description sets forth numerous specific details such asexamples of specific systems, components, methods, and so forth, inorder to provide a good understanding of several embodiments of thepresent invention. It will be apparent to one skilled in the art,however, that at least some embodiments of the present invention may bepracticed without these specific details. In other instances, well-knowncomponents or methods are not described in detail or are presented insimple block diagram format in order to avoid unnecessarily obscuringthe present invention. Thus, the specific details set forth are merelyexemplary. Particular implementations may vary from these exemplarydetails and still be contemplated to be within the scope of the presentinvention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.In addition, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” When the term “about” or “approximately” is usedherein, this is intended to mean that the nominal value presented isprecise within ±30%.

Although the operations of the methods herein are shown and described ina particular order, the order of the operations of each method may bealtered so that certain operations may be performed in an inverse orderor so that certain operation may be performed, at least in part,concurrently with other operations. In another embodiment, instructionsor sub-operations of distinct operations may be in an intermittentand/or alternating manner.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reading and understanding theabove description. The scope of the invention should, therefore, bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A chamber component comprising: a body; a firstprotective layer on at least one surface of the body, the firstprotective layer comprising a plasma resistant ceramic, wherein thefirst protective layer has a thickness of greater than approximately 50microns and comprises a plurality of cracks and pores; and a conformalsecond protective layer that covers at least a portion of the firstprotective layer, the second protective layer comprising a plasmaresistant rare earth oxide, wherein the second protective layer has athickness of less than 50 microns, has a porosity of less than 1%, andseals the plurality of cracks and pores of the first protective layer.2. The chamber component of claim 1, wherein: the body comprises atleast one of a metal, a metal alloy, or a ceramic having metalimpurities; and the second protective layer acts as a barrier to preventprocess gases from penetrating the plurality of cracks and pores in thefirst protective layer and reacting with metals in the body.
 3. Thechamber component of claim 1, wherein the first protective layer is aplasma-sprayed layer comprising at least one of Al₂O₃, Y₂O₃, SiO₂, or aceramic compound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.4. The chamber component of claim 1, wherein the second protective layeris an ion assisted deposition (IAD) deposited layer comprising at leastone of Y₂O₃, Y₃Al₅O₁₂, Y₄Al₂O₉, or a ceramic compound comprising Y₄Al₂O₉and a solid-solution of Y₂O₃—ZrO₂.
 5. The chamber component of claim 1,wherein the second protective layer is an ion assisted deposition (IAD)deposited layer comprising at least one of Er₂O₃, Er₃Al₅O₁₂, YF₃,Er₄Al₂O₉, or ErAlO₃.
 6. The chamber component of claim 1, wherein thesecond protective layer is a complex oxide composition that comprisesY₂O₃, ZrO₂, Er₂O₃, and Al₂O₃.
 7. The chamber component of claim 6,wherein the complex oxide composition comprises about 25 mol % Y₂O₃,about 25 mol % ZrO₂, about 25 mol % Er₂O₃, and about 25 mol % Al₂O₃. 8.The chamber component of claim 1, wherein the second protective layercovers the first protective layer on the at least one surface of thebody at one or more first locations but not at one or more secondlocations.
 9. The chamber component of claim 1, where the secondprotective layer is one layer in a protective layer stack that comprisesthe second protective layer and a third protective layer with adifferent composition from the second protective layer, wherein thesecond protective layer has an amorphous structure and the thirdprotective layer has a crystalline structure.
 10. The chamber componentof claim 1, wherein a bottom of the second protective layer thatcontacts the first protective layer has a first oxygen concentration anda top of the second protective layer has a higher second oxygenconcentration.
 11. A method comprising: performing ion assisteddeposition (IAD) to deposit a second protective layer on at least aportion of a first protective layer that is on a surface of an article,the second protective layer comprising a plasma resistant rare earthoxide, wherein the second protective layer has a thickness of less than50 microns, has a porosity of less than 1%, and seals a plurality ofcracks and pores of the first protective layer.
 12. The method of claim11, further comprising: cooling the article during deposition of thesecond protective layer to maintain the article at a temperature ofbelow approximately 150° C.
 13. The method of claim 11, wherein thearticle is a chamber liner of an etch reactor, the chamber liner havinga hollow cylindrical shape, and wherein performing IAD to deposit thesecond protective layer comprises: positioning a target at a firstopening of the article; coating a first portion of an interior of thearticle; subsequently positioning the target at a second opening of thearticle; and coating a second portion of an interior of the article. 14.The method of claim 11, further comprising performing the followingprior to depositing the second protective layer: identifying one or moreregions of the article that will exhibit a high erosion rate relative toother regions of the article; and masking the article with a mask,wherein the identified one or more regions of the article are exposed bythe mask, and wherein the second protective layer will coat the one ormore identified regions of the article.
 15. The method of claim 11,wherein performing the IAD comprises: setting a working distance betweena target material and the article to less than 1 meter.
 16. The methodof claim 11, further comprising: performing a plasma spraying process todeposit the first protective layer on the surface of the article, thefirst protective layer comprising a plasma resistant ceramic, whereinthe first protective layer has a thickness of greater than approximately50 microns and comprises at least one of Al₂O₃, Y₂O₃, SiO₂, or a ceramiccompound comprising Y₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.
 17. Themethod of claim 11, wherein the second protective layer comprises atleast one of Y₂O₃, Y₃Al₅O₁₂, Y₄Al₂O₉, or a ceramic compound comprisingY₄Al₂O₉ and a solid-solution of Y₂O₃—ZrO₂.
 18. The method of claim 11,wherein the second protective layer comprises at least one of Er₂O₃,Er₃Al₅O₁₂, YF₃, Er₄Al₂O₉, or ErAlO₃.
 19. The method of claim 11, furthercomprising: performing IAD to deposit a third protective layer on thesecond protective layer, wherein the third protective layer has athickness of less than approximately 50 microns and comprises a secondceramic different from the first ceramic, the second ceramic selectedfrom the group consisting of: Y₃Al₅O₁₂, Y₄Al₂O₉, Er₂O₃, Gd₂O₃,Er₃Al₅O₁₂, Gd₃Al₅O₁₂ and a ceramic compound comprising Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂.
 20. The method of claim 11, wherein thesecond protective layer is a complex oxide composition that comprisesY₂O₃, ZrO₂, Er₂O₃, and Al₂O₃.